canonicalizing values (like "interning" or "hash-consing").

Any value of comparable type may be canonicalized with the new
`Make[T]` function, which produces a reference to a canonical copy of
the value in the form of a `Handle[T]`.
Two `Handle[T]` are equal if and only if the values used to produce the
handles are equal, allowing programs to deduplicate values and reduce
their memory footprint.

reliable, and efficient software.

![Gopher image](https://golang.org/doc/gopher/fiveyears.jpg)
*Gopher image by [Renee French][rf], licensed under [Creative Commons 4.0 Attributions license][cc4-by].*

Our canonical Git repository is located at https://go.googlesource.com/go.
There is a mirror of the repository at https://github.com/golang/go.

Unless otherwise noted, the Go source files are distributed under the

	stdPackages []string                     // names, omitting "unsafe", internal, and vendored packages
	importMap   map[string]map[string]string // importer dir -> import path -> canonical path
	importDir   map[string]string            // canonical import path -> dir

}

func NewWalker(context *build.Context, root string) *Walker {
	w := &Walker{
		context:  context,
		root:     root,
		features: map[string]bool{},

//
// RET
//
//	LRETRN	comma // asm doesn't support the trailing comma.
//	{
//		outcode(int($1), &nullgen, 0, &nullgen);
//	}
	SYSCALL
	BEQ	R1, 2(PC)
	RET


// More JMP/JAL cases, and canonical names JMP, CALL.

	JAL	foo(SB) // CALL foo(SB)
	BEQ	R1, 2(PC)
	JMP	foo(SB)
	CALL	foo(SB)
	RET	foo(SB)

	// unary operation
	NEGW	R1, R2 // 00011023
	NEGV	R1, R2 // 0001102f

	// RET
	//
	//	LRETRN	comma // asm doesn't support the trailing comma.
	//	{
	//		outcode(int($1), &nullgen, 0, &nullgen);
	//	}
	SYSCALL
	BEQ	R1, 2(PC)
	RET


	// More JMP/JAL cases, and canonical names JMP, CALL.

	JAL	foo(SB)	// CALL foo(SB)
	BEQ	R1, 2(PC)
	JMP	foo(SB)
	CALL	foo(SB)
	RET	foo(SB)

	// unary operation
	NEGW	R1, R2 // 00011023
	CLZ	R1, R2 // 70221020

//	}
	PLD	(R1)
	PLD	4(R1)

//
// RET
//
//	LTYPEA cond
//	{
//		outcode($1, $2, &nullgen, 0, &nullgen);
//	}
	BEQ	2(PC)
	RET

// More B/BL cases, and canonical names JMP, CALL.

	BEQ	2(PC)
	B	foo(SB) // JMP foo(SB)
	BL	foo(SB) // CALL foo(SB)
	BEQ	2(PC)
	JMP	foo(SB)
	CALL	foo(SB)

// CMPF and CMPD are special.
	CMPF F1, F2
	CMPD F1, F2

	CASPW	(R6, R7), (R8), (R4, R5)             // 047d2608
	CASPD	(R2, R3), (R2), (R8, R9)             // 487c2248

// RET
	RET
	RET	foo(SB)

// B/BL/B.cond cases, and canonical names JMP, CALL.
	BL	1(PC)      // CALL 1(PC)
	BL	(R2)       // CALL (R2)
	BL	foo(SB)    // CALL foo(SB)
	BL	bar<>(SB)  // CALL bar<>(SB)
	B	foo(SB)    // JMP foo(SB)
	BEQ	1(PC)
	BEQ	2(PC)